1. Field of the Invention
This invention relates to gondola type railway cars having open top shell construction. Railway cars of this type are particularly suited to unit train operations and may be used for hauling woodchips, coal or other bulk material with the cars being readily adapted for rotary discharge.
2. Description of the Prior Art
As discussed in U.S. patent application Ser. No. 574,481, filed May 5, 1975, by Roy W. Miller and Jack E. Gutridge, now U.S. Pat. No. 3,964,399 issued June 22, 1976, which is incorporated by reference herein, railway gondola cars of a conventional design are provided with a car floor which is supported and rests upon the top of a center sill projecting outwardly from the ends of the car. The floor is carried on cross bearers which are connected at their inner ends to the webs of the center sill and extend outwardly from opposite sides thereof to the side sills. The side and end walls of the car are coupled at each of the upper corners of the car by an overlying corner cap.
Because gondolas are less rigid against torsion, they are therefore vulnerable to severe end-to-end torsional twisting to which other types of railway freight cars can more easily resist. Additionally, experience has shown that during rail use over rough or high speed tracks generally oscillatory end-to-end torsional loading on the gondola causes simultaneous lateral and longitudinal deflection of the upper portions of the car walls. The character and relationship of this deflection is illustrated in FIG. 9 which shows plan view outlines of a car having undeflected walls in solid lines and the upper portions of the walls of the same car illustratively deflected in phantom lines.
Attention is also directed to U.S. Pat. No. 789,854 which shows diagonal bracing extending normal to the sides of a vehicle. U.S. Pat. No. 1,262,301 shows cross-bracing parallel to the end wall of a car, and U.S. Pat. No. 922,969 shows a chain brace spanning the upper and lower ends of the side walls of a vehicle. None, however, solve the problem of rigidizing the car body by braces which bisect the corners and extend into the car and attach at their upper ends to the corners and at their lower ends to cross-members, such as bolsters which extend beneath the car body and thus effectively resisting destructive flexure hereinafter discussed.
Considering the above and the drawing, it can be seen that the oscillatory parallelogram motion of the upper portions of the car walls accentuates fatigue loading and fracture of the car body and particularly the overlying corner caps.